1. Field of the Invention
The present invention relates to digital image processing, and more particularly to an image processing method and apparatus that adds a blur to an image.
2. Description of the Related Art
As a photographing technique of a camera, a photographing method, for emphasizing a target object by intentionally blurring a portion other than the object (e.g. background), is known. A problem, however, is that a sufficient blur cannot be generated in a compact camera, since the depth of field cannot be decreased because the image sensor is small. Therefore recently a technique is proposed to generate an image where the background or the like is blurred by adding a blur later by digital image processing. For example, in the case of a blur generation apparatus disclosed in Patent Document 1, blur processing by convolution processing is performed for each equal depth range using a photographed image and a depth map, and the depth boundary is synthesized by special processing, so as to efficiently generate a blurred image. Patent Document 2 discloses an image generation system to efficiently generate a blurred image by determining the blur target pixels based on the depth value (depth map), and shifting the texture image by a predetermined amount.    Patent Document 1: Japanese Patent Application Laid-Open No. 2005-25766    Patent Document 2: Japanese Patent Application Laid-Open No. 2001-160153